It has become well established that there are major public health benefits from regular endoscopic examinations as an aid to the early detection of disease of internal structures such as the alimentary and excretory canals and airways, e.g., the colon, esophagus, lungs, uterus, bladder, bronchi, and other organ systems. A conventional imaging endoscope used for such procedures comprises a flexible tube with a fiber optic light guide that directs illuminating light from an external light source to the distal tip where it illuminates the region (i.e. tissue, occlusion object) to be examined. Frequently, additional optical components are incorporated to adjust the spread of the light exiting the fiber bundle and the distal tip. An objective lens and fiber optic imaging light guide communicating with a camera at the proximal end of the scope, or an imaging camera chip at the distal tip, produce an image that is displayed to the operator. In addition, most endoscopes include one or more working channels through which medical devices such as biopsy forceps, snares, fulguration probes, and other tools may be passed.
Navigation of the endoscope through complex and tortuous paths is critical to success of the examination with minimum pain, side effects, risk, or sedation to the patient. To this end, modern endoscopes include means for deflecting the distal tip of the scope to follow the pathway of the structure under examination, with minimum deflection or friction force upon the surrounding tissue, and to survey targeted examination sites. Control cables similar to bicycle brake cables are carried within the endoscope body in order to connect a flexible portion of the distal end to a set of control knobs at the proximal endoscope handle. By manipulating the control knobs, the operator is usually able to steer the endoscope during insertion and direct it to a region of interest.